1. Field of the Invention
The present invention relates to a latch mechanism for use in a portable electronic apparatus, such as a lap-top type computer and word processor. More particularly, this invention relates to a latch mechanism having a latch member which, in an apparatus including a display unit and a base unit having a keyboard, is brought into engagement with the base unit when the display unit is rotated to a closed position (i.e., a position covered keyboard) to hold the display unit in the closed position.
2. Description of the Related Art 2.
Recently, portable electronic apparatuses, such as a lap-top type portable computer and word processor having a keyboard and flat panel type display unit, have become increasingly popular.
This type of apparatus includes a base unit having a keyboard and flat panel type display unit supported on the base unit. The display unit is supported on the base unit and is rotatable, by a hinge mechanism, between a closed position where the keyboard is covered and an open position where the keyboard is exposed.
The display unit has a front surface exposed at the front end of the apparatus when it is rotated to the closed position. A latch mechanism is provided on the front surface of the display unit. A portable electronic apparatus including a latch mechanism is disclosed, for example, in U.S. patent application Ser. No. 07/542,041 filed Jun. 22, 1990 and U.S. patent application Ser. No. 07/542,248 filed Jun. 22, 1990. The latch mechanism includes a latch member made of an elastically deformable synthetic resin material and one end of the latch member is fixed by latch member is detachably latched to the front end of the base unit when the display unit is rotated to a closed position. By so doing, the display unit is held in the closed position.
In the conventional latch mechanism, the latch member and base unit are held in an engaged state under an elastic force of the latch member. Since the latch member is elastically deformed each time the display unit is closed or opened, it is necessary, from the viewpoint of the durability of the latch member, to increase the thickness of the latch member to some extent to enhance the rigidity of the latch member. An increase in the rigidity of the latch member necessarily leads to an increase in its own elastic force. When the display unit is rotated to the closed position, the latch member is reasonably engaged with the base unit and the display unit is positively held in the closed position without being loosened
When the display unit is opened from the closed position, it is necessary to place the user's finger on the latch member and to force the latch member into deformation in a direction to disengage the latch member from the base unit. If, in this case, the latch member has a larger resiliency, a greater elastic force of the latch member acts as a greater resistance on his or her finger. Then, a heavier burden is imparted to his or her finger in the disengagement of the latch member from the base unit and hence an undue force is applied to his or her finger. Therefore, there is room for further improvement on the operability of the latch member as involved when the display unit is rotated to an open position.